Irish-British physicist notable for his studies concerning electrical charge and electric conduction in gases. He made the first direct measurement of the electrical charge. His discovery of the phenomenon of the electron avalanche is called the Townsend discharge. He was Wykeham Professor of physics at the University of Oxford. In 1914, he was awarded the Hughes Medal for his discoveries. He studied at Trinity College, Dublin and graduated with a BA in mathematics in 1890. He later became a research student at Trinity College, Cambridge.
